Fluid packaging and dispensing devices of the bottle/pouch type are well known. These devices generally comprise a container with a rigid shell, in which is placed a shrinkable flexible pouch which shrinks in proportion as the product is extracted from it. The expulsion of the product out of the pouch may be obtained by means of an airless pump or without air recuperation or under the pressure of a propellant gas acting in the bottle on the wall of the pouch. As regards the expulsion of the product out of the pouch by means of a pump without air recuperation, a vent is provided, generally in the bottom or in the neck of the bottle, so that the outside air can penetrate into the space located between the bottle and the pouch during each actuation of the pump, thus allowing the pouch to shrink, with sufficient pressure at the same time being maintained on its walls, while keeping the product contained in the pouch, which remains airless. An exemplary embodiment according to this technique is described in the patent FR 2,723,356 relating to a device comprising a pouch made from flexible plastic, such as polyethylene or polypropylene, in a rigid container, the neck of which comprises an air inlet. Pouch systems are also known in which the top part is reinforced in order to make it easier to fasten it to the rigid bottle, and the patent application WO 0058021 describes a pouch according to this technique, although the product volume restored by this type of pouch is generally unsatisfactory, since the deformation of the pouch is limited essentially to the cylindrical part of its wall, and the rate of restoration then cannot hope to reach 90%. This is a disadvantage which is the more serious the higher the value of the product contained in the pouch, and because an appreciable quantity of the product is then lost for the user.
This likewise applies to the pouch described in the patent GB 2,184,491, which comprises two parts having a substantially equivalent volume, the upper part being rigidified by means of ribs, while the flexible lower part shrinks, at the same time returning to the upper part.
The difficulties encountered in these known techniques are often associated with the folds which are formed by the wall of the pouch during its shrinkage and which may limit the fluid dispensing efficiency by forming product retention volumes, and with the difficulty of ensuring a satisfactory leaktightness of the pouch, thus making it possible to maintain the intactness of the product contained in it. To be precise, the products which the pouches contain are often sensitive to oxidation under the action of atmospheric oxygen and may deteriorate if air is introduced into the pouch. The leaktightness faults are often found in the region of the junction of the pouch and of the pump. They may also arise due to a certain porosity of the materials used for producing the pouch. Finally, the folds formed by the wall of the pouch during its shrinkage may cause tears liable to allow air to pass through which then reaches the product contained in the pouch.
Another exemplary embodiment of a bottle/pouch is described in the patent FR 2,770,834 which relates to a device intended for avoiding the piercing and tearing of the pouch during the emptying of the latter. For this purpose, the pouch, produced from flexible material, such as plastic film or aluminum foil, contains a free float preventing an excessive shrinkage of the pouch and thus limiting the risks of tearing. However, the devices of this type have the disadvantage of not ensuring a freeing of the entirety of the product contained in the pouch and consequently of giving rise to appreciable losses of product.
Pouches, the lower part of which comprises a plurality of concertinas, are also known. The document FR 2,669,306 describes a pouch comprising a concertinaed lower part which is progressively accommodated in the frustoconical volume of the rigid upper part, without being laid against the latter. Another example is described in the patent GB 2,083,142 which deals with a pasty product applicator comprising a shrinkable pouch which comprises a plurality of concertinas.
These multiple-concertina pouches have disadvantages. To be precise, during filling, air inclusions risk being trapped in the folds, all the more because the viscosity of the product intended for filling the pouch is high. Moreover, the multiple concertinas have the effect of retaining the product and consequently of reducing the restoration rate of the pouch.
The pumps usually assigned to the flexible pouches must ensure good leaktightness and be capable of functioning both in the vertical position and in an inclined position. The patent FR 2,669,379 describes a metering pump affording good leaktightness even in the event of a change in position, of the axial piston type carrying a sliding floating piston comprising three flap valves. The patent FR 2,726,810 describes an example of a pump without an air inlet, in which the lower flap valve is flexible and frustoconical, while the upper flap valve is carried by a disk placed at the base of the hollow stem of the tappet.